In the grinding of surfaces of revolution on workpieces, there is usually a reference surface of revolution to which the surface to be ground is to be accurately geometrically related. Usually, it is possible to use the reference surface to mount the workpiece on the workhead, so that the wheelhead will lie at a known predetermined relationship to it. In such a situation it is relatively easy to relate the finished surface to the reference surface. For instance, in the case of grinding an internal bore on the outer race of a roller bearing, the outer surface of the race can either be clamped or it can rest on fixed shoes while the spindle of the workhead rotates it. Some workpiece configurations prohibit this type of treatment, however. This is true, for instance, if the reference surface is not available for support of the workpiece, as is the case where a finger or flange extends axially around the surface. It is also true in the situation in which the reference surface itself is to be ground at the same time as other surfaces of revolution that are related to it. Attempts to handle such awkward workpieces in the past have involved mounting the workpiece on the workhead spindle by use of various chucking, jig, and trial-and-error methods, but none of these lend themselves to any kind of production manufacture. For one thing, they all would involve a very long setup time, during which time the machine is non-productive; in the case of a very expensive grinding machine this means that the operation on the workpiece is a very expensive one. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide a grinding machine for finishing workpieces on a production basis.
Another object of this invention is the provision of a grinding machine for generating surfaces of revolution on a workpiece in precise geometric relationship to a reference surface of revolution in the case where the reference surface of revolution cannot be used for supporting the workpiece.
A further object of the present invention is the provision of a grinding machine for finishing a surface of revolution on one end of an elongated workpiece where the axis of the surface of revolution is at a substantial angle to most of the length of the workpiece.
It is another object of the instant invention to provide a grinding method for finishing a surface of revolution where the surface is at least partly enveloped in a skirt or the like, so that radial access to the surface is not available.
A still further object of the invention is the provision of a grinding machine having a chuck for holding odd-shaped workpieces during the grinding of surfaces of revolution.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.